Relationship between anti-Xa level achieved with prophylactic low-molecular weight heparin and venous thromboembolism in trauma patients: A systematic review and meta-analysis
Bibliographic record
Abstract
BACKGROUND: Trauma patients have simultaneously high venous thromboembolism (VTE) and bleeding risk. Optimal chemoprophylaxis regimens remain unclear. This study aims to answer three questions for trauma patients. Is there any association between anti-Xa and VTE? Does dose adjustment improve prophylactic anti-Xa rates? Does dose adjustment improve anti-Xa adequacy and VTE compared with standard dosing? METHODS: Systematic search of MEDLINE, Embase, Scopus, and Web of Science occurred in May 2021. Two author reviews included trauma studies that evaluated low molecular weight heparin chemoprophylaxis, reported anti-Xa level, and evaluated more than one outcome. Data were dually extracted and estimated effects were calculated using RevMan 5.4 applying the Mantel-Haenszel method. Analysis 1 compared patients with peak anti-Xa of 0.2 IU/mL or greater or trough 0.1 IU/mL or greater to those with lower anti-Xa using VTE as the primary outcome. Analysis 2 reported the effect of dose adjustment on anti-Xa. Analysis 3 compared standard dosing to dose adjustment with the primary outcome being anti-Xa adequacy; secondary outcomes were VTE, pulmonary embolism, and bleeding complications. RESULTS: There were 3,401 studies evaluated with 24 being included (19 retrospective studies, 5 prospective studies). In analysis 1, achieving adequate anti-Xa was associated with reduced odds of VTE (4.0% to 3.1%; odds ratio [OR], 0.52; p = 0.03). Analysis 2 demonstrated that 768 (75.3%) patients achieved prophylactic anti-Xa with adjustment protocols. Analysis 3 suggested that dose-adjusted chemoprophylaxis achieves prophylactic anti-Xa more frequently (OR, 4.05; p = 0.007) but without VTE (OR, 0.72; p = 0.15) or pulmonary embolism (OR, 0.48; p = 0.10) differences. In subgroup analysis, anti-Xa dose adjustment also suggested no VTE reduction (OR, 0.68; p = 0.08). CONCLUSION: Patients with higher anti-Xa levels are less likely to experience VTE, and anti-Xa guided chemoprophylaxis increases anti-Xa adequacy. However, dose adjustment, including anti-Xa guided dosing, may not reduce VTE. LEVEL OF EVIDENCE: Systematic Review Meta-Analysis, Level IV.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.011 | 0.027 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.018 | 0.040 |
| Bibliometrics | 0.006 | 0.008 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".